4L80E Transmission Fluid Type?

[Coonass77]

Hi Folks, quick question...
What is everyone running for trans fluid in the your 4 speeds? TM obviously calls for Dex3, but Dex6 is supposed to be backwards compatible and an acceptable replacement for (and improvement over) Dex3. Anyone have experience with the Dex6, or should I stick with Dex3? I don't know that it matters, but the truck is 2004 M1123. Thanks!

 

[patracy]

Dex 3 is fine for it. Dex6 is a better fluid, it's from a full syn. stock. You can go longer between service intervals with dex6. But in the case of most MV's, that's not really an issue.

IMHO, I'd just run dex3 for this, unless there was a good sale on dex6 at the time.

 

[Coug]

Either DEX 3 or DEX 6 work just fine.

Dex6 is backwards compatible in transmissions. It is NOT backwards compatible in the power steering system, so the choices are either keep multiple fluids on hand for the truck, or keep everything as DEX 3 and only stock one fluid.
(The military likes to minimize the number of different fluids used, but that doesn't mean the ones they use are the best ones for the job, just that they will work)

 

[Coonass77]

Thanks for the replies and guidance, guys!